In terms of performance, there is nothing wrong with a $20 Chinese MMDVM board connected up to a Pi Zero. The benefit you get from a more expensive branded Hotspot is better support... If you are comfortable with some simple mechanical assembly and tinkering with Linux at the command line, then don't be afraid of assembling a hotspot with a cheap MMDVM card - you'll save a fair amount of money.
Martin (G8FXC)
I did exactly this. The MMDVM card was from Amazon, and so was the Pi-Zero. It cost a bit more, but the Pi's are really hard to find.
It works flawlessly, no issues at all. Mine is working with an Xfinity Gateway that I installed last month. The hardest thing to do with 70+ year old eyes was soldering the pins on the header.